If we admit that there is a deep unity in all Sacred Scripture, then there must be a starting point and a term, since the Holy Spirit wanted to reveal to us the mystery of God through a story. Where does Scripture end? With Saint John, with the Johannine writings. The whole official Revelation ends with the Johannine writings. Because of this, it is in the light of Saint John that we must read all Scripture and understand all Revelation...
But why did the Holy Spirit choose Saint John to give us the last secrets? Because John was the beloved disciple ... John was also the one who received Mary as a mother – this is also very important. The Word of God is indeed a living word, bound to "the good earth" and therefore to Tradition. The first moment of Tradition took place in Mary’s heart.
Mary is Christian Tradition at its source. It was therefore necessary that the writer who eventually gave us the mystery of God’s Word be the very one who was intimately bound to the mystery of the "good earth." Thus John was both bound to the heart of Christ and was bound to Mary. He was bound to her because he received her at the very moment when Mary was next to Jesus and experienced the mystery of the Cross.
Father Marie-Dominique Philippe (1912-2006)
Founder of the Congregation of Saint John
Excerpts from Following the Lamb, Editions Saint Paul - 2005